Speed change mechanism for phonograph turntables



March 17, 1953 R. G. METZNER SPEED CHANGE MECHANISM FOR PHONOGRAPH TURNTABLES Filed June l2, 1948 2 SHEETS-SHEET l March 17, 1953 R. G. METZNER SPEED CHANGE MECHANISM FOR PHONOGRAPH TURNTABLES 2 SHEETS-SHEET 2 Filed June l2, 1948 3 mma/whom /of/fr G. METZ/VER.,

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Patented Mar. 17, 1953 UNITED STATES AT'ENT ortica My invention relates to aspeed change mechanisrn for phonograph turntables and more specifically to a device to connect a constant speed electric motor to a phonograph turntable which forms a positive drive and has a change speed mechanism incorporated therein so that the turntable' can be rotated at various constant speeds.

The phonograph records sold to the general A' public usually are tatd at a relatively high rate of speed While those manufactured for radio Ya change speed mechanismv between a phonograph and a constant speed motor which does not require complicated sets of gears or clutches.

Other objects and advantages of my invention will be apparent from the following description I- of the preferred embodiments.

In the drawings: K

Figure i isa top plan view, partially broken away, ofmy invention. A

Figure 2` is an elevational View with the turntable in section.

Figure 3 is a sectional View taken on the line 3-3 of Figure 2.

Figure 3a is a sectional view taken on the line 3-3 of Figure 2 showing the device in its opposite position from that in Figure 3.

Figure 4 is a sectional view taken on the line 4 4 of Figure 1.

Figure 5 is a sectional view taken on the line 5-5 of Figure l.

Figure 5a is a fragmentary sectional View similar to Figure 5 showing the change speed mechanism in its opposite position from Figure 5.

Figure 6 is a perspective view.

Figure '7 is a top plan view partially broken away of a modification of my invention.

Figure 8 is a sectional View taken on the line 8--8 of Figure '7.

Figure 9 is a sectional View taken on the line 9 9 of Figure 8.

A device constructed in accordance with my invention comprises a hanger plate I from which is supported a constant speed motor II. A journal I2 forms a pivot for the pinion I3 to which is attached a phonograph turntable I4 which has thereon a rubber mat I to protect phonograph records.

hanger I0 extends.

Cutaway openings I6 and I'I are' positioned in the turntable I4 to give access to the change speed mechanism by flipping back the rubber inat I5 as shown in Figure 6.

The motor shaft` I8 of the constant speed motor II has a sleeve I9 mounted thereon. A'n elongated detent 2U is formed in the shaft I8. A ball 2I locks the sleeve I9 to the shaft I8' when positioned in the hole 22 and the detent 20. The b all 2| is held in position by a spring clip y The lengtli of the detent 20 permits the sleeve I9 to be inoved up and down upon the shaft I 8. n

Upon the upper surface of' the hanger I0 is a projection 25 on which is pivotally mounted a lever 28 by rneaiis of tl'ie slot 21. The lever 26'has a collar 21d mounted thereon to encompass and hold the shaft 28 upon which an idler 29" is rotatively mounted. The idler 29 has around its' perimeter a covering of rubber 3u, or other material, which frictionally engages the inner surface 3I of the turntable III. When the idler 29 is driven the saine drives the turntable I by means of friction upon the inner surface 3|. *Y i y I Adjacent the collar 27d in Athe lever (23 is a hole 32 through which a bolt 33 attached to the vA nut 34 maintains the lever 26 in a flat relation to the hanger IIJ, but permits it to be moved in relation to the projeotion 25 and the bolt 33 in any direction as the hole 32 is much larger in diameter than the bolt 33.

A spring 35 connected to the projection 36 upon the lever 26 and a boss 31 upon the hanger IG tends to move the lever 26 in a direction so that the rim of the idler 29 is in contact with the motor shaft I3 and the surface 3|. The motor shaft I8, the idler 23 and the surface 3I of the turntable I4 are constructed in such a size with relation to the speed of the constant speed motor II that when the motor is operated and the idler 2S engages the shaft I8, the turntable will be rotated at a constant speed which is the desired speed for playing transcription records.

'I'he sleeve I9 has a collar 38 thereon which has an exterior diameter that when contacting the idler gear 29 as shown in Figure 3a., the rotation of the shaft I8 will speed up the rotation of the idler 29 and turntable I4 to that of the ordinary commercial phonograph record. To accomplish this change in speed the rubber mat I 5 is ipped back, the turntable rotated until it is in a position Where one of the openings I6 or I1 is in the position shown in Figure 6 wherein it is possible to reach through the opening I6. By reaching through the opening I6 and moving the lever 26 sideways, the collar 38 can be moved up upon the shaft I8 until it is in a position directly opposite the idler 29 as shown in Figure a. The lever 26 is then released and the spring 35 will tension the idler 29 against the perimeter of the collar 38, thus forming a direct drive from constant speed motor II to the turntable I4 at a higher speed than when the motor shaft I8 was in contact with the idler 29.

In Figures 7-9, inclusive, is shown a modiiication of my invention. In this modification the motor shaft I8 has a collar 40 permanently afxed thereto to form a contacting surface for the idler 29. The idler 29 is mounted upon a pivot bearing 4I which is supported on telescoping slide plate 42. In this form of my invention, instead of moving the collar 48 up and down on the motor shaft, the slide plate 42, which supports the bearing 4I for the idler 29, is moved up and down so that the idler can bear either against the motor shaft I8 or against the collar 40. This is accomplished by having the slide plate 42 formed to make a U-shape with legs 43 and 44 Slidably movable in slots 45 in the guide plate 46. Pins 41 prevent the legs 43 and 44 from being drawn completely from the slots 45. A boss 49 projects from the upper surface of the guide plate 46 and has a bore 48 extending therethrough. A shaft 50 is riveted to the hanger plate I0, and the bore 48 is adapted to slide upon the shaft 50. An elongated detent 5I is formed in the shaft 50. A ball 52 is positioned in the hole 53 and held there by the spring clip 54 to lock the boss 49 upon the shaft 50. This type of construction permits the guide plate 46 to be raised `or lowered upon the shaft 50 and to thus cause the circumference of the idler 29 to bear directly on the motor shaft I8 or the collar 49, thus changing the speed ratio. A spring 55 tensions the idler against the driver and the turntable.

An advantage of my invention over all other turntable change speed mechanisms is that the mechanisml can be readily reached and shifted from one speed to the other through the hole I6.

For this reason the entire apparatus can be placed in a, small cabinet as no linkage, gears or levers are run out to change the speed.

While I have described the preferred embodiments of my invention, I am not limited to any of the details of construction herein set forth except as described in the following claims.

I claim:

l. In a device of the character described, a hanger, a constant speed motor mounted thereon and having a, drive shaft, a turntable rotatively journaled on said hanger, a lever movably attached to said hanger and rotatively carrying an idler wheel thereon, said idler wheel adapted to engage the perimeter of said shaft and said turntable to transmit rotation of said shaft to said turntable, and a sleeve on said shaft adapted to slide thereon and having a collar which is slidable into position lbetween said shaft and said idler to increase the speed of rotation of said idler wheel and said turntable.

2. In a device of the character described, a hanger, a constant speed motor mounted thereon and having a drive shaft, a turntable rotatively journaled on said hanger, a lever movably attached to said hanger and rotatively carrying an idler wheel thereon, said idler wheel adapted to engage the perimeter of said shaft and said turntable to transmit rotation of said shaft to said turntable, a Spring adapted to hold said idler gear in engagement with said shaftV and said turntable, and a sleeve on said shaft adapted to slide thereon and having a collar which is slidable into position between said shaft and said idler to increase the speed of rotation of said idler wheel and said turntable.

ROBERT G. METZNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,047,733 Harrison July 14, 1936 2,260,319 Hoehn Oct. 28, 1941 2,381,079 Pittman, Jr Aug. 7, 1945 2,438,264 Bender, Jr Mar. 23, 1948 2,438,265 Metzner Mar. 23, 1948 

